Multilayer piezoelectric transformer

Abstract

A multi-layer piezoelectric transformer (PT) is provided having an insulation layer having an input electroactive ceramic layer bonded to one of its major faces and an output electroactive ceramic layer bonded to its other major face. The input layer is electroded on both major faces and is poled in the thickness direction. The output layer has segmented electrodes patterned on its two opposing major faces and portions of the output layer are alternatingly poled in opposite directions across the output layer's thickness. The configuration of the poling and electrodes places adjacent portions of the output layer electrically in series.

I claim:  
     
       1. A piezoelectric transformer, comprising: 
       a transformer input portion, said transformer input portion comprising;  
       a first input layer of electroactive ceramic having first and second opposing major faces;  
       a first input electrode bonded to said first major face of said first input layer; and  
       a second input electrode bonded to said second major face of said first input layer;  
       a transformer output portion, said transformer output portion comprising;  
       a first output layer of electroactive ceramic having first and second opposing major faces, and first and second nonparallel bisectors;  
       a first intermediate electrode bonded to and substantially covering said first major face of said first output layer on a first side of said first bisector;  
       a second intermediate electrode bonded to and substantially covering said first major face of said first output layer on a second side of said first bisector;  
       said first and second intermediate electrodes being electrically isolated from each other on said first major face of said first output layer;  
       a first output electrode bonded to and substantially covering said second major face of said first output layer on a first side of said second bisector;  
       a second output electrode bonded to and substantially covering said second major face of said first output layer on a second side of said second bisector and on a first side of said first bisector; and  
       a third output electrode bonded to and substantially covering said second major face of said first output layer on said second side of said second bisector and on a second side of said first bisector;  
       said first, second and third output electrodes being electrically isolated from each other on said second major face of said first output layer; and  
       an isolation layer having first and second opposing major faces;  
       said first major face of said isolation layer being bonded to said first or second opposing major face of said first input layer;  
       said second major face of said isolation layer being bonded to said first or second opposing major face of said first output layer.  
     
     
       2. The piezoelectric transformer according to  claim 1 , 
       wherein said first input layer has a first cross-section in a plane parallel to said first and second opposing major faces;  
       and wherein said first output layer has a second cross-section in a plane parallel to said first and second opposing major faces;  
       said first and second cross-sections being substantially equal circular cross-sections.  
     
     
       3. The piezoelectric transformer according to  claim 1 , 
       wherein said first input layer has a first cross-section in a plane parallel to said first and second opposing major faces;  
       and wherein said first output layer has a second cross-section in a plane parallel to said first and second opposing major faces;  
       said first and second cross-sections being substantially equal rectangular cross-sections.  
     
     
       4. The piezoelectric transformer according to  claim 2 , 
       wherein said first and second bisectors comprise first and second perpendicular diameters;  
       and wherein said first and second perpendicular diameters divide said first and second faces of said first output layer into first, second, third and fourth substantially equal quadrants.  
     
     
       5. The piezoelectric transformer according to  claim 3 , 
       wherein said first and second bisectors comprise first and second perpendicular bisectors;  
       and wherein said first and second perpendicular bisectors divide said first and second faces of said first output layer into first, second, third and fourth substantially equal quadrants.  
     
     
       6. The piezoelectric transformer according to  claim 4 , 
       wherein said first input layer is polarized in the thickness direction normal to a plane parallel to said first and second opposing major faces of said first input layer;  
       and wherein said first output layer is polarized in the thickness direction normal to a plane parallel to said first and second opposing major faces of said first output layer;  
       the direction of polarization in said thickness direction of said first and third quadrants being opposite to the direction of polarization in said thickness direction of said second and fourth quadrants.  
     
     
       7. The piezoelectric transformer according to  claim 5 , 
       wherein said first input layer is polarized in the thickness direction normal to a plane parallel to said first and second opposing major faces of said first input layer;  
       and wherein said first output layer is polarized in the thickness direction normal to a plane parallel to said first and second opposing major faces of said first output layer;  
       the direction of polarization in said thickness direction of said first and third quadrants being opposite to the direction of polarization in said thickness direction of said second and fourth quadrants.  
     
     
       8. The piezoelectric transformer according to  claim 1 , wherein said transformer input portion further comprises: 
       a second input layer of electroactive ceramic having first and second opposing major faces; and  
       a third input electrode being bonded to said first major face of said second input layer;  
       said second major face of said input layer being bonded to said second input electrode.  
     
     
       9. The piezoelectric transformer according to  claim 1 , wherein said transformer output portion further comprises: 
       a second output layer of electroactive ceramic having first and second opposing major faces, and third and fourth nonparallel bisectors;  
       said second major face of said second output layer being bonded to second major face of said first output layer and to said first, second and third output electrodes;  
       said first, second and third output electrodes substantially covering said second major face of said second output layer;  
       said first, second and third output electrodes being electrically isolated from each other on said second major face of said second output layer;  
       a fourth output electrode bonded to and substantially covering said first major face of said second output layer on a first side of said third bisector;  
       a fifth output electrode bonded to and substantially covering said first major face of said second output layer on a second side of said third bisector and on a first side of said fourth bisector; and  
       a sixth output electrode bonded to and substantially covering said first major face of said second output layer on said second side of said third bisector and on a second side of said fourth bisector; said fourth, fifth and sixth output electrodes being electrically isolated from each other on said first major face of said second output layer.  
     
     
       10. The piezoelectric transformer according to  claim 8 , 
       wherein said first and second bisectors comprise third and fourth perpendicular diameters;  
       and wherein said third and fourth perpendicular diameters divide said first and second faces of said second output layer into fifth, sixth, seventh and eighth substantially equal quadrants;  
       and wherein said first and third diameters are parallel;  
       and wherein said second and fourth diameters are parallel.  
     
     
       11. A piezoelectric transformer, comprising: 
       a transformer input portion, said transformer input portion comprising;  
       a first input layer of electroactive ceramic having first and second opposing major faces;  
       a first input electrode bonded to said first major face of said first input layer; and  
       a second input electrode bonded to said second major face of said first input layer;  
       a transformer output portion, said transformer output portion comprising;  
       a first output layer of electroactive ceramic having first and second opposing major faces, and first, second and third nonparallel bisectors;  
       a first intermediate electrode bonded to and substantially covering a first arc segment of said first major face of said first output layer;  
       said first arc segment extending between said first bisector and said third bisector across said second bisector and being less than 180 degrees;  
       a second intermediate electrode bonded to and substantially covering a second arc segment of said first major face of said first output layer;  
       said second arc segment extending between said second bisector and said third bisector across said first bisector and being less than 180 degrees;  
       a third intermediate electrode bonded to and substantially covering a third arc segment of said first major face of said first output layer;  
       said third arc segment extending between said first bisector and said second bisector across said third bisector and being less than 180 degrees;  
       said first, second and third intermediate electrodes being electrically isolated from each other on said first major face of said first output layer;  
       a first output electrode bonded to and substantially covering a first arc segment of said second major face of said first output layer;  
       said first arc segment extending between said first bisector and said third bisector and not across said second bisector and being less than 180 degrees;  
       a second output electrode bonded to and substantially covering a second arc segment of said second major face of said first output layer;  
       said second arc segment extending between said first bisector and said second bisector and not across said third bisector and being less than 180 degrees;  
       a third output electrode bonded to and substantially covering a third second arc segment of said second major face of said first output layer;  
       said third arc segment extending between said first bisector and said second bisector across said third bisector and being less than 180 degrees;  
       a fourth output electrode bonded to and substantially covering a fourth arc segment of said second major face of said first output layer;  
       said fourth arc segment extending between said first bisector and said third bisector across said second bisector and being less than 180 degrees;  
       said first, second, third and fourth output electrodes being electrically isolated from each other on said second major face of said first output layer; and  
       an isolation layer having first and second opposing major faces;  
       said first major face of said isolation layer being bonded to said first or second opposing major face of said first input layer;  
       said second major face of said isolation layer being bonded to said first or second opposing major face of said first output layer.  
     
     
       12. The piezoelectric transformer according to  claim 11 , 
       wherein said first input layer has a first cross-section in a plane parallel to said first and second opposing major faces;  
       and wherein said first output layer has a second cross-section in a plane parallel to said first and second opposing major faces;  
       said first and second cross-sections being substantially equal circular cross-sections.  
     
     
       13. The piezoelectric transformer according to  claim 12 , 
       wherein said first, second and third bisectors comprise first, second and third diameters having a 120 degree angle orientation relative to each other;  
       and wherein said first, second and third diameters divide said first and second faces of said first output layer into first, second, third, fourth, fifth and sixth substantially equal sextants.  
     
     
       14. The piezoelectric transformer according to  claim 13 , 
       wherein said first input layer is polarized in the thickness direction normal to a plane parallel to said first and second opposing major faces of said first input layer;  
       and wherein said first output layer is polarized in the thickness direction normal to a plane parallel to said first and second opposing major faces of said first output layer;  
       the direction of polarization in said thickness direction of said first, third and fifth sextants being opposite to the direction of polarization in said thickness direction of said second, fourth and sixth sextants.